Rotor mounting

ABSTRACT

A rotor is pivotally mounted on the lower end of a drive shaft which is suspended for pendular movement. A flexible coupling connects the rotor to the shaft whereby the rotor may be driven by the shaft upon rotation thereof while being permitted to pivot in respect of the shaft, and an elastic return means interposed between the rotor and the shaft tends to move the rotor opposite to the pivoting movement thereof.

iJite Mates atet 1191 Retali et al.

[54] ROTGR MOUNTING [75] Inventors: Roger Retall', Saint Cloud; AndreMercler, La Madelene, both of France; Claude Billot, Alger, Algeria [73]Assignee: Fives Lille-Call, Paris, France [22] Filed: Mar. 16, 1971 [21]Appl. No.: 124,798

[30] Foreign Application Priority Data Mar. 17, 1970 France ..7009383'52 U.S.Cl ..64/ 7,34/-58 s1 InLCl ..F16d3/02 58 Field of Search....1.....34/'5s; 64/7; 210/366, 367

[ 5 6] References Cited UNITED STATES PATENTS 2,936,894 5/1960 Hertrich"210/366 51 Apr. 3, 1973 Bruenig ..2l0/366 Motycka ..2l0/366 FOREIGNPATENTS OR APPLICATIONS 4l8,607 10/1910 France ..21o 366 102,322 3/1899Germany ..2l0/366 Primary Exai'ninerl(enneth W. Sprague Attorney-KurtKelman [5 7 ABSTRACT in respect of the shaft, and an elastic returnmeans in-- terposed between the 'rotor and the shaft tends to move therotor opposite to the pivoting movement thereof.

12 Claims, Drawing Figures PATENTEBAPR3 1975 3.724.238

sum 2 OF 4 M D w \MMP IMM m m 5 5 I B 4 I a 2 2 w A J FIG.2

INVENTORS. ROGER RETALI ANDRE MERCIER CLAUDE BILLOT BY Kw KM AGENTPATENTEU APR 3 I975 sum 3 BF 4 FIG.3

49a as INVENTORS. ROGER RETALI ANDRE MERCIER CLAUDE BILLOT BY AGENTPATENTEUAPRS B73 3. 724,238

sum u 0F 4 FIGA v so

' 62' f 70 J E 68 I N VENTORS.

ROGER RETALI ANDRE MERCIER CLAUDE BILLOT BY mm W AGENT ROTOR MOUNTINGThe present invention relates to an apparatus which comprises a framesupport, a vertically extending rotary drive shaft, means for suspendingthe drive shaft on the frame support for pendular movement in respectthereto, and a rotor mounted on the lower end of the drive shaft. Anexample of such an apparatus is a centrifugal drier wherein the rotor isconstituted by a basket containing the product to be dried.

In conventional apparatus of this type, the rotor is rigidly fixed toits drive shaft causing vibrations which are transmitted to the framesupport when the rotor is not perfectly balanced during rotation.Furthermore, when the rotor turns at a critical speed which correspondsto the oscillatory cycle of the suspended assembly, the resultingunbalance causes oscillations of considerable amplitude which subjectthe frame support to excessive tensions. It is, therefore, of obviousinterest to hold down the critical speed as much as possible to reducethese loads on the frame support.

It is a primary object of this invention to reduce the loads transmittedto the bearing support of the drive shaft and, as a consequence, toattenuate the vibrations of the support when the rotor is out ofbalance, and to lower the critical speed.

The above and other objects are accomplished in accordance with theinvention by providing a joint pivotally mounting the rotor on the lowerend of the drive shaft. The joint is a flexible coupling connecting therotor to the shaft whereby the rotor may be driven by the shaft uponrotation thereof while being permitted to pivot in respect of the shaft.An elastic return means is interposed between the rotor and the shaftand tends to move the rotor opposite to the pivoting movement thereof.

The flexible coupling and the elastic return means may be combined intoa unitary system.

According to one feature of the present invention, the elastic returnmeans comprises two coupling plates respectively fixed to the rotor andthe shaft, and an elastically deformable device mounted between theplates whereby one of the plates may be displaced angularly in respectof the other plate. The elastically deformable devicemay be an annularmember or a series of annularly disposed blocks of deformable material,such as rubber, or an annular spring or a series of annularly disposedsprings interposed between the coupling plates.

According to another feature of this invention, a damping device may beassociated with the elastic return means to restrain the oscillations ofthe rotor in respect to the drive shaft and to oppose the change ofdirection of the axis of the shaft-rotor assembly so as to limit theamplitude of this change of direction to an admissible value. Thedamping device is interposed between the drive shaft and the rotor forrestraining the pivoting movements of the rotor and may comprise atransverse element, such as an annular disk coaxial with the shaft,mounted on the shaft for gliding and angular movement in respect of theaxis of the drive shaft, and clamping means, such as a pair of clamps,fixed on the rotor and clampingly engaging the transverse element, suchas by engaging the disk between the clamps.

In certain machines and for certain purposes, it is necessary ordesirable to hold the axis of the rotor fixed during rotation thereof.This is particularly true for centrifugal driers with a cylindricalbasket from which the dried product is removed by means of a scrapermounted on a fixed support. To prevent the scraper from damaging thefilter cloth or screen covering the wall of the basket, the basket mustbe restrained from oscillating during this operation. Accordingly, acentering device may be mounted on the drive shaft to permit the pivotalmovements of the rotor in respect of the drive shaft in an inoperativecondition of the centering device but to maintain the rotor and shaftcoaxial in its operative condition.

In a preferred embodiment, the centering device comprises a pair ofcomplementary and interengageable conical members, one glidingly mountedon the drive shaft for movement in an axial direction and the otherfixed to the rotor. Pressure fluid operated means moves the one conicalmember from the inoperative condition of the device wherein the membersare out of engagement into the operative condition wherein the oneconical member engages the other conical member.

Similarly, a damping and centering device may be provided forrestraining or preventing pendular movement of the drive shaft inrespect of the frame support.

The above and other objects, advantages and features of the presentinvention will become more apparent from the following detaileddescription of certain now preferred embodiments thereof, taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a side elevational view, primarily in axial section, of acentrifugal drier constructed according to this invention;

FIG. 2 is a like view of another embodiment of a centrifugal drier;

FIG. 3 is a partial axial section showing yet another embodiment of themounting of the basket of the drier on its drive shaft, as well ascompensating and centering devices controlling the relative movementbetween basket and shaft; and

FIG. 4 is another partial axial section showing a centering deviceassociated with the support of the drive shaft on its bearing support.

Referring now to the drawing and first to FIG. 1, there is shown acylindrical basket 10 of a centrifugal drier, which basket is suspendedon frame support 14 for pendular movement. The basket constitutes therotor of the illustrated apparatus and the rotor mounting includes avertically extending drive shaft 12 having a lower end, and a swivel orball-and-socket joint 13 pivotally mounting the basket 10 on the lowerend of the drive shaft. The center of the spherical joint is posi tionedon the axis of the drive shaft and at or near the center of gravity ofthe basket. The joint includes a flexible coupling of a generally knowntype which connects the basket to the shaft whereby the basket may bedriven by the shaft upon rotation thereof while being permitted to pivotabout joint 13 in respect of the shaft.

This flexible coupling is shown to comprise twocoupling plates 16, 17respectively fixed to hub 24 of basket 10 and drive shaft 12, and anelastically deformable annular member 15 mounted between the plateswhereby one of the plates may be displaced angularly in respect of theother plate in respect of the shaft axis. The annular member 15 may beof rubber, for instance, and could be readily replaced by an equivalentelastically deformable device, such as a series of annularly disposedrubber blocks or springs. Furthermore, this device constitutes anelastic return means interposed between the basket and the shaft andtending to move the basket opposite to the pivoting movement thereof soas to maintain the basket and shaft coaxial to each other.

The upper end of drive shaft 12 is suspended on the frame support 14 forpendular movement in respect thereto. This suspension includes ahemispherical balland-socket joint 19, 20 consisting of a dished bearingsupport 20 mounted on the frame support and a complementary bearing race19 mounted on the dished support for swivel motion in respectthereto,'the dished support having a central bore through which thehearing race extends, and roller bearings 18 supporting the drive shaft12 in bearing race 19.

The pendular movement of the drive shaft about the joint is damped by anelastic return means constituted by an elastic device 21, similar to thedevice 15, interposed between the bearing race 19 and an annular flangel 1 fixed to the bearing support 20.

A drive motor 23 is mounted atop of the frame support 14 by means ofbracket 29. An output shaft 31 extends from the motor and is coupled tothe upper end of the drive shaft for rotating the drive shaft. Theillustrated coupling between the motor shaft 26 having a fixed axis andthe drive shaft 12 having a pendular axis consists of a flexiblecoupling 22 of a known type whose center coincides with the center ofball-andsocket joint 19, 20.

In the modified centrifugal drier of FIG. 2, like reference numeralshave been used to designate like parts operating in a like manner toobviate redundancy in the description. This figure shows the position ofthe basket and the drive shaft 12' when the assembly rotates at greatspeed and the basket is out of balance. In this embodiment, the mountingof the drive shaft differs from that of FIG. 1.

As shown, a universal joint 25 connects the upper end of drive shaft 12for pendular movement to the lower end of motor shaft 26 having a fixedaxis. The motor shaft is rotatably journaled in bearing 28 mounted atopthe frame support 14. The motor shaft is coupled to the motor 23 bycoupling 27 which may be rigid. Obviously, the universal joint 25 may bereplaced by any type of joint permitting the drive shaft to be angularlydisplaced in respect of the fixed axis of the motor shaft to permitpendular movement of the drive shaft, such angular displacement beingillustrated in FIG. 2, the drive shaft 12' being inclined in respect ofmotor shaft 26 and basket 10 being inclined in respect of drive shaft12. In this manner, the center of gravity of the basket may bepositioned in the fixed axis of motor shaft 26' without exerting asubstantial load on motor shaft bearing 28.

In the embodiment of FIG. 3, there is provided between the basket 10 andthe drive shaft 12" not only a flexible coupling and an elastic returnmeans, as in the abovedescribed embodiments, but also a centering devicecapable of maintaining the basket and drive shaft coaxial in respect ofeach other, when necessary, as well as a compensating device forrestraining the oscillations of the basket in respect of the driveshaft.

As in the previously described embodiments, the basket 10' is mountedpivotally on drive shaft 12" by means of a ball-and-socket joint 13'. Inthis embodiment, however, the flexible coupling connects the basket andthe drive shaft for common rotation by a gear including a collar 38fixed to the drive shaft and a collar 39 fixed to the hub of the basket.The two collars have interengaging teeth 31 curved in an axial directionso as to permit angular displacement of one collar in respect of theother collar in respect of the drive shaft axis while remaining engaged.An annular crankcase 37 is mounted on collar 38 and contains alubricating medium 36 wherein the gear teeth 31 are immersed.

The elastic return means of the flexible coupling is constituted by aseries of springs 40 annularly disposed between the flanges 38a, 39a ofthe collars. The coupling is protected by a fluid-tight cover 41 placedthereover and receiving the drive shaft through a central bore in thecover, and a flexible membrane 42 interconnecting the lower ends of thecollars.

The centering device comprises a female conical hub member 45 fixed tothe basket and a complementary male conical member 43 glidingly mountedon the drive shaft for movement in an axial direction into and out ofengagement with the conical hub member 45. The male conical member 43 isnormally pressed axially downwardly out of engagement with the conicalhub member 45 by spring 44 engaging shoulder 44a on drive shaft 12 and ashoulder in the conical member 43, respectively.

The illustrated means for moving the conical member 43 from the showninoperative condition of the centering device wherein the conicalmembers are out of engagement into the operative condition wherein theconical member 43 engages the conical hub member 45 is pressure fluidoperated. It includes an annular pressure chamber 47 defined betweenconical member 43 and a flexible membrane 48 fluid tightly clamped alongits annular periphery between the member 43 and a flange 46. The centralportion of the membrane 48 is supported on an annular platform 49 fixedto the drive shaft 12' and forming a fluid tight seal with the platform.A gasket 52 between the conical member 43 and the drive shaft providesan upper fluid tight seal for the pressure chamber 47.

A source of pressure fluid (not shown) is connected to a central bore 51in the drive shaft by means of connection for supplying a pressure fluidto chamber 47 when it is desired to move the centering device into itsoperative condition. When fluid is supplied to the pressure chamberunder pressure, the conical member 43 is axially moved against the biasof spring 44 and into engagement with complementary conical hub member45 so as to prevent angular movement of the two members in respect ofeach other about joint 13' and thus to hold the basket 10 and driveshaft 12" coaxial.

Furthermore, a damping device is shown interposed between the driveshaft 12" and the basket 10 for restraining the pivoting movements ofthe basket in respect of the shaft. The illustrated damping devicecomprises transverse element constituted by an annular disk 53 coaxialwith the shaft and mounted thereon for gliding and angular movement inrespect of the axis of shaft 12", the disk being supported by a swiveljoint 54 freely glidable on the shaft. Clamping means constituted in theillustrated embodiment by a pair of clamps 56, 56 is fixed on the hub 45of the basket. The clampscarry friction members 57 wherebetween the disk53 is engaged. The clamping force is provided by springs 55 whose biasmay be adjusted by nuts 55a threadedly mounted on bolts 55b whichconnect the clamps to the basket hub 45. Obviously, the arrangementcould be reversed, i.e., the clamps could be fixed to the drive shaftand the disk could be mounted on the basket.

The centering and damping devices are positioned within the conical hubmember 45 which is closed by a fluid tight flexible membrane 58 at thebottom of the conical hub member and a fluid tight annular gasket 59positioned between the clamps 56, 56 along the periphery thereof.

The damping device opposes movements causing a change of direction ofthe axis of the drive shaft-basket assembly or limits the amplitude ofsuch movements to an admissible value. When such a change of directiontakes place, the drive shaft turns slowly about the vertical axispassing through the center of the joint suspending the shaft forpendular movement while the basket turns about its axis of inertia. Thisresults in an angular movement of the basket in respect of the shaftabout joint 13, which causes displacement of disk 53 between clamps 56,56. The friction forces opposing the displacement of the disk are thusopposed to the movement of change of direction of the axis.

It may be noted that the centering and damping devices illustrated inFIG. 3 could also be used at the level of articulated suspension of thedrive shaft to prevent or limit oscillations of the drive shaft inrespect to the motor shaft to which the drive shaft is coupled by auniversal joint or a flexible coupling, as shown, respectively, in FIGS.1 and 2.

FIG. 4 illustrates another type of centering device used at the point ofarticulated suspension of the drive shaft. This device, too, is normallyinoperative to permit pendular movements of the drive shaft in respectof the frame support in the inoperative position thereof, andmaintaining the drive shaft axis fixed in the operative condition.

A bearing support 69 mounted on the frame support (not shown in thisfigure) holds a dished support 70 forming a ball-and-socket joint withcomplementary bearing race 63 in a manner similar to the pendularsuspension of the drive shaft shown in FIG. 1. The dished support 70 hasa central bore through which the bearing race 63 extends, and rollerbearings support the drive shaft 12" in the bearing race for swivelmotion of the shaft in respect of the bearing support 69. A flexiblecoupling 22 connects the drive shaft to motor shaft 26 The centeringdevice comprises a flanged member 60 fixed to the pendularly movablebearing race 63 wherein the drive shaft is rotatably joumaled, and acooperating ram member 61 radially displaceable into and out ofengagement with the flanged member 60 by a pressure fluid operatedpiston 62 moving each ram ally inwardly into engagement with the flangedmember to immobilize the bearing race 63 and thus the drive shaftagainst oscillatory motion about the joint 63, 70.

An elastic return means for the drive shaft is provided by springs 66mounted in bearing support 69 and exerting a resilient radial force uponthe drive shaft in opposition to the pendular movement of the shaft whenthe centering device is in the inoperative condition shown, i.e., whenthe rams 61 are disengaged from flanged member 60. The bias of springs66 may be adjusted by knob 68 threadedly mounted in the bearing support69 for axial movement in relation to the spring.

If the centering devices for keeping the axis of the drive shaft fixedin respect of the frame support and for maintaining the position ofbasket and drive shaft fixed are operated, dried matter may be removedfrom the inside of the basket by a fixedly mounted scraper withoutdamaging the basket. Since this operation is effected at low rotaryspeed, it makes no difference that the entire assembly is rigid in thiscondition of the centering devices.

Since the critical rotary speed of the drive shaftbasket assembly isrelatively high when the two centering devices are in the blockingposition and low when they are inoperative so as to permit articulation,the discharge speed may be chosen between these two critical speeds,which avoids having to break through a critical speed at the moment whenit is desired to block or unblock the articulations.

Obviously, the joint pivotally mounting the rotor on the drive shaft maybe a universal joint, such as a Cardan joint, or any other type ofthrust joint capable of absorbing axial forces. Such a joint may replacethe ball-and-socket joint and the flexible coupling connecting the shaftto the rotor. In this case, as illustrated by way of example in theshaft suspension of FIG. 4, which obviously may be applied to thepivotal mounting of the rotor on the shaft end, the elastic return meansmay be constituted by springs exerting a pressure on the shaft or therotor, respectively, as well as elastic rings or annularly disposedelastic blocks.

While the apparatus has been described and illustrated in connectionwith centrifugal driers such as used particularly in sugar refineriesfor separating sugar crystals from their mother liquor, it will beobvious to those skilled in the art that the present invention will beuseful in any machine where a rotor is suspended at the lower end of avertical drive shaft, such as certain impellers, for instanceventilators or pumps.

We claim:

1. In an apparatus comprising a frame support; a vertically extendingrotary drive shaft having a lower end, means for suspending the driveshaft on the frame support for pendular movement in respect thereto; arotor; and a joint pivotally mounting the rotor on the lower end of thedrive shaft, said joint including a flexible coupling connecting therotor to the shaft whereby the rotor may be driven by the shaft uponrotation thereof while being permitted to pivot in respect of the shaft:a damping device interposed between the drive shaft and the rotor fordamping the pivoting movements of the rotor in respect of the shaft.

2. The apparatus of claim 1, wherein the joint is a ball-and-socketjoint.

3. The apparatus of claim 1, wherein the joint is a universal joint.

4. The apparatus of claim 7, wherein the elastic return means comprisestwo coupling plates respectively fixed to the rotor and the shaft, andan elastically deformable device mounted between the plates whereby oneof the plates may be displaced in respect of the other one of theplates.

5. The apparatus of claim 4, wherein the elastically deformable deviceis an annular member of deformable material interposed between theplates.

6. The apparatus of claim 4, wherein the elastically deformable deviceconsists of spring means interposed between the plates.

7. The apparatus of claim 1, further comprising an elastic return meansinterposed between the rotor and the shaft and tending to move the rotoropposite to the pivoting movements thereof.

8. The apparatus of claim 1, wherein the damping device comprises atransverse element mounted on the drive shaft for gliding and angularmovement in respect of the axis of the shaft, and clamping means fixedon the rotor and clampingly engaging the transverse element.

9. The apparatus of claim 8, wherein the transverse element is anannular disk coaxial with the shaft, and the clamping means consists ofa pair of clamps between which the disk is engaged.

10. The apparatus of claim 1, further comprising a normally inoperativecentering device permitting the pivotal movements of the rotor inrespect of the drive shaft in the inoperative condition thereof, andmaintaining the rotor and shaft coaxial in the operative condition.

l l. The apparatus of claim 10, wherein the centering device comprises apair of complementary and interengageable conical members, one of theconical members being glidingly mounted on the drive shaft for movementin an axial direction and the other one of the conical members beingfixed to the rotor, and means for moving the one conical member from theinoperative condition of the device wherein the members are out ofengagement into the operative condition wherein the one conical memberengages the other conical member.

12. The apparatus of claim 1, further comprising a normally inoperativecentering device permitting the pendular movements of the drive shaft inrespect to the frame support in the inoperative condition thereof, andmaintaining the drive shaft axis fixed in the operative condition.

1. In an apparatus comprising a frame support; a vertically extendingrotary drive shaft having a lower end, means for suspending the driveshaft on the frame support for pendular movement in respect thereto; arotor; and a joint pivotally mounting the rotor on the lower end of thedrive shaft, said joint including a flexible coupling connecting therotor to the shaft whereby the rotor may be driven by the shaft uponrotation thereof while being permitted to pivot in respect of the shaft:a damping device interposed between the drive shaft and the rotor fordamping the pivoting movements of the rotor in respect of the shaft. 2.The apparatus of claim 1, wherein the joint is a ball-and-socket joint.3. The apparatus of claim 1, wherein the joint is a universal joint. 4.The apparatus of claim 7, wherein the elastic return means comprises twocoupling plates respectively fixed to the rotor and the shaft, and anelastically deformable device mounted between the plates whereby one ofthe plates may be displaced in respect of the other one of the plates.5. The apparatus of claim 4, wherein the elastically deformable deviceis an annular member of deformable material interposed between theplates.
 6. The apparatus of claim 4, wherein the elastically deformabledevice consists of spring means interposed between the plates.
 7. Theapparatus of claim 1, further comprising an elastic return meansinterposed between the rotor and the shaft and tending to move the rotoropposite to the pivoting movements thereof.
 8. The apparatus of claim 1,wherein the damping device comprises a transverse element mounted on thedrive shaft for gliding and angular movement in respect of the axis ofthe shaft, and clamping means fixed on the rotor and clampingly engagingthe transverse element.
 9. The apparatus of claim 8, wherein thetransverse element is an annular disk coaxial with the shaft, and theclamping means consists of a pair of clamps between which the disk isengaged.
 10. The apparatus of claim 1, further comprising a normallyinoperative centering device permitting the pivotal movements of therotor in respect of the drive shaft in the inoperative conditionthereof, and maintaining the rotor and shaft coaxial in the operativecondition.
 11. The apparatus of claim 10, wherein the centering devicecomprises a pair of complementary and interengageable conical members,one of the conical members being glidingly mounted on the drive shaftfor movement in an axial direction and the other one of the conicalmembers being fixed to the rotor, and means for moving the one conicalmember from the inoperative condition of the device wherein the membersare out of engagement into the operative condition wherein the oneconical member engages the other conical member.
 12. The apparatus ofclaim 1, further comprising a normally inoperative centering devicepermitting the pendular movements of the drive shaft in respect to theframe support in the inoperative condition thereof, and maintaining thedrive shaft axis fixed in the operative condition.